--- title: "K-factor in chess" url: "https://georgelichess.com/glossary/k-factor.md" canonical_url: "https://georgelichess.com/glossary/k-factor" last_updated: "2026-11-07" type: "reference" summary: "The K-factor is the multiplier in an Elo-style rating update that sets how many points a rating can move after a result." related: ["https://georgelichess.com/glossary/elo-rating.md", "https://georgelichess.com/glossary/fide-rating.md", "https://georgelichess.com/glossary/provisional-rating.md", "https://georgelichess.com/glossary/rating-performance.md", "https://georgelichess.com/glossary/rating-system.md", "https://georgelichess.com/glossary/category/tournaments-ratings-titles.md", "https://georgelichess.com/glossary.md"] --- # K-factor in chess > **For AI agents:** the complete index of GeorgeLiChess pages is [llms.txt](https://georgelichess.com/llms.txt). Every page is also served as markdown at its URL plus .md. The K-factor is the multiplier in an Elo-style rating update that sets how many points a rating can move after a result. The K-factor is the multiplier in an Elo-style rating update that sets how many points a rating can move after a result; a larger K makes the rating react faster. After a game or event, an Elo-style system compares your actual score with the score your rating predicted, and the K-factor scales the gap. With K equal to 20, scoring one point more than expected adds 20 points. With K equal to 10, the same surprise adds only 10. FIDE sets K by status (Rating Regulations, clause 8.3.3): 40 for a player new to the list until they have completed events totalling 30 games; 20 while the rating stays under 2400; 10 once the published rating has reached 2400, even if it later dips below; and 40 for any player, until the end of the year of their 18th birthday, while their rating stays under 2300. The same clause caps K times the games on a list in one rating period at 700 and lowers K where that product would be exceeded. US Chess does not use a fixed table. Its published method sets K to 800 divided by the sum of an effective game count and the games played in the event, so K falls smoothly as evidence accumulates, with different rules for some high-rated players in dual-rated events. The logic is simple: a rating with little evidence behind it should move quickly, and one backed by hundreds of games slowly. That is why juniors and newcomers swing more than long-established masters. Read [provisional rating](https://georgelichess.com/glossary/provisional-rating.md), [rating performance](https://georgelichess.com/glossary/rating-performance.md) and [FIDE rating](https://georgelichess.com/glossary/fide-rating.md) next. Also called: K factor. A neighboring idea is [Elo rating](https://georgelichess.com/glossary/elo-rating.md). An Elo rating is a number that estimates playing strength from results: the gap between two ratings predicts the expected score, and wins and losses move each player's rating up or down. How "K-factor" applies to your own results depends on where you stand now, and the [improvement plans by rating band](https://georgelichess.com/improve.md) show what players near your rating work on. ## Related terms - [Elo rating](https://georgelichess.com/glossary/elo-rating.md) - [FIDE rating](https://georgelichess.com/glossary/fide-rating.md) - [Provisional rating](https://georgelichess.com/glossary/provisional-rating.md) - [Rating performance](https://georgelichess.com/glossary/rating-performance.md) - [Rating system](https://georgelichess.com/glossary/rating-system.md) ## Guides that go further - [Chess ratings explained](https://georgelichess.com/chess-ratings-explained.md): What a rating measures, how FIDE, Lichess, US Chess and chess.com compute theirs, and why the numbers differ. - [Average chess rating and a good chess rating](https://georgelichess.com/chess-rating-percentiles.md): What share of active Lichess players are rated above 800, 1200, 1500, 1800 or 2000, by time control. - [How to get a FIDE rating](https://georgelichess.com/how-to-get-a-fide-rating.md): The Handbook rules for a first FIDE rating: five rated games, the 1400 floor, the two 1800 draws and a worked example. ## Sources - FIDE Handbook B.02 FIDE Rating Regulations, effective 1 March 2024 (Clause 8.3.3), read 2026-10-21: https://handbook.fide.com/chapter/B022024 - US Chess, The US Chess Rating System (Glickman and Doan), dated 6 April 2026 (Section 4.2), read 2026-10-21: https://new.uschess.org/sites/default/files/media/documents/us_chess_rating_system_specs-2026-04-06.pdf [Book your first lesson](https://georgelichess.com/book.md) and George Li reviews your games and builds a study plan around them. Questions about lessons: write to hello@georgelichess.com. ## Related - [Elo rating in chess](https://georgelichess.com/glossary/elo-rating.md) - [FIDE rating in chess](https://georgelichess.com/glossary/fide-rating.md) - [Provisional rating in chess](https://georgelichess.com/glossary/provisional-rating.md) - [Rating performance in chess](https://georgelichess.com/glossary/rating-performance.md) - [Rating system in chess](https://georgelichess.com/glossary/rating-system.md) - [Chess terms: Tournaments, ratings and titles](https://georgelichess.com/glossary/category/tournaments-ratings-titles.md) - [Chess terms glossary: plain definitions](https://georgelichess.com/glossary.md)